In Your Veins
by CharlieSwagron
Summary: Post-Smells Like Teen Spirit 6x15. No major spoilers whatsoever, just some fluff and smut between everybody's favorite engaged duo.


**Disclaimer: I don't own Castle and unfortunately, I never will.**

**A/N: I got inspired to write something after the latest episode and this is what came out. Nothing major from the episode is spoiled. This is my second time writing smut so I'm still trying to get used to it somewhat. Thank you and enjoy reading.**

"So…was the dance everything you'd hoped it would be?" Beckett asked on their way home.

"At the risk of sounding like a total cliché, I'd have to say that no, it wasn't. It was better than anything I could ever have imagined," Castle told her.

A red light brought the car to a halt as Beckett raised an eyebrow and glanced at him. "Oh? Even more than 25 years later?"

"Of course." The smile he gave her outshone the stars that currently filled the nighttime sky. "Only because I was there with you tonight, though. With anyone else, it just wouldn't have been as magical. And what about you? Would your prom have been anything close to this?"

She shook her head. "Absolutely not. If I'd gone to my senior prom, I know exactly how the night would've ended. I'd dance with some teenage boy I'd have only known for a couple months until we left early to go back to his place where we'd have sex."

His eyes were burning holes into her. "And how's this night gonna end?"

She bit her lip and gave him a sly smile. "Play your cards right and it might end up the same way."

"Except I'm not a teenager."

"You most certainly are not," she agreed with a quick side glance at his crotch. The car's temperature felt like it had gone up about ten degrees. The prospect of tearing Castle's clothes off when they got back to the loft had Beckett pressing down harder on the gas. The muscles in her leg jumped slightly when Castle laid a palm on her upper thigh.

The rest of the ride was spent in tense silence. Castle's thumb kept making small circles on the inside of her thigh. His eyes never took themselves off her.

When they finally reached the loft, she heaved an internal sigh of relief. Once inside, they stepped onto the elevator, sharing the ride with a family of four. The two stood in the back corner, hands linked as the elevator ascended floor after floor.

Beckett was barely able to control herself. She had hoped that the elevator would've been empty save them, but obviously her wish had not been granted. The air was so thick with tension, she was almost positive that the family there felt it too.

Unfortunately for Beckett and Castle, said family apparently lived on the floor beneath the loft, meaning nearly the entire ride was spent in their company. When the elevator dinged on the writer's floor, the two made their way to the front door.

"Alexis?" the detective asked. The girl had been staying at the loft for the past couple days due to an argument she and Pi had had.

"At a friend's," he replied, pulling out his key.

"Martha?"

"At a '_friend's,_'" he said with a grimace at mentioning his mother's after hours activities.

"Good," she whispered before pushing him up against the door, key half-sitting in the lock. She nipped at the back of his neck as her hands reached around his front, undoing his belt and untucking his shirt.

Unprepared for her onslaught, Castle fumbled with the key, trying to turn it to let them inside the loft.

"Beckett, it's kind of hard to concentrate when you're, um, doing _that,_" he told her.

"Castle, if you don't get us inside that door right now, I'll have no problem doing this out here." She emphasized her point by tugging at his coat and yanking it off, holding it in one arm.

The man quickly realized she wasn't kidding so he grabbed a hold of the key, shoved it the rest of the way in the handle, and turned it so the door would unlock.

They stumbled through the doorway, Beckett tossing his coat away as she threw off hers. Castle yanked the key out of the lock and stuffed it in his pocket, slamming the door before attacking his fiancée's mouth with his own.

The writer slammed her back into the door, his fingers hurriedly undoing the buttons on the vest she was wearing. She shrugged it off and went to work on her shirt. Castle had apparently thought that she was taking too long so he took matters into his own hands. Grabbing the edges of her shirt, he wrenched it open, sending buttons flying in all directions.

"That was one of my favorites, you know," she scolded.

"I'll buy you another." He sealed his mouth over hers once more. His tongue locked and wrestled with hers as a moan sounded from her throat. Both of his hands slithered down to unbutton her pants. He pulled the zipper down, the sound echoing through their ears. Suddenly, he spun her around, her front to the door.

Guiding her palms to press against the wood, he instructed, "Don't move them."

She whimpered as she felt his hands slide down her sides. Her ripped shirt was still on, but that did nothing to hinder Castle's journey. One hand dipped into the lacy panties she was wearing. When the hand cupped her fully, she felt her knees grow weak. Beckett had just steadied her legs when Castle fastened his mouth to her neck, sucking and biting to no end.

He let his middle finger run through her again and again, feeling the wetness that was gathered there. He gently circled her clit, leaving off just enough pressure to make her want to beg. Bringing his finger down to her entrance, he slowly pushed it in, relishing in the groan that came from the detective's lips.

The hand he'd left unoccupied came up to her bra-clad breasts and latched onto one. He squeezed and kneaded lightly while his finger continued to pump into her.

Castle glanced up briefly and noticed Beckett's fingernails attempting to embed themselves into his door. He really hoped she wouldn't leave any claw marks. That would be extremely difficult to explain to his daughter and mother and would only lead to embarrassment—who would suffer more: him or Alexis? He didn't know and didn't _want_ to know the answer to that question.

Groaning, he turned his attention back to the beautiful woman practically riding his hand. _Stop it, Rick. Now is _not _the time to be thinking of your daughter and your mother._

Retracting his hand, much to the disappointment of his fiancée, Castle forced her to turn around and ripped her ruined shirt off. Beckett, on the other hand, was working on unbuttoning _his_ shirt. Swatting her hands away, he began the task himself. Not one to be still or patient at a time like this, she tugged her boots and socks off.

Knowing that he'd follow, the detective strutted towards their bedroom, making sure to add an extra sway to her hips as he blatantly stared at her ass. She heard him walk after her as soon as he'd divested himself of his shirt.

Once in the bedroom, she unclasped her bra and let it drop to the floor without any care whatsoever. She turned just in time to see her fiancé close and lock the door behind them. Even though they had the place to themselves for the night, there was no telling who might end up barging in on them. They'd had enough interruptions the past few months to last a lifetime.

Castle stalked towards her predatorily, his bare chest heaving as he breathed. His normally crystal blue eyes were nearly black with desire.

Beckett laid back on the bed as the man hovered over her. He brought his lips down to her chest and took one of her nipples in his mouth. The woman gasped as her hands clutched fistfuls of his thick hair. He lightly bit the rosy bud, adding just enough pain to keep it pleasurable. Moving to the neglected breast, he showered it with the same attention he'd devoted to the other.

Trailing a series of open-mouthed kisses down her toned abs, Castle found his exploration come to a halt as he was met with the waistband of her pants. He gripped the waistband and pulled both her pants and panties down her mile-long legs.

Running his hands up and down her smooth legs, he attacked the inside of one tight with his mouth. Moving up, he peppered kisses across her pubic bone, just above where she needed him most. Her hips bucked in effort to get him to touch her there, but he brought a hand up to rest firmly on her stomach, stilling her.

Laving at the crease between her leg and sex, he smirked to himself at the moan she tried to hold in. After a moment, he decided to be kind and end the torture. Placing his mouth on her clit, he sucked, causing her hips to shoot up in surprise and pleasure.

It felt like her body was about to burst at the seams. Their kiss at the dance had been sweet and romantic as they confirmed their first dance song, but it was also charged with longing and want. It had been at least a week since the last time they'd had sex and to Beckett, that was one week too long. Feeling Castle's lips and tongue and teeth work together to bring her gratification was almost too much for her.

"Castle," she moaned at last.

Hearing his name, the writer looked up and grinned smugly. It pleased him to no end whenever she said his name in bed.

One of her hands grasped his hair and pushed his head back down to her while the other came up to tangle in her own messy locks.

Taking the hint, the man went back to work, this time taking a cue from her and adding his hands to the mix. The quick flicks of his tongue never ceased as he pushed two fingers inside her. Stroking her walls, he took his head away and pressed his thumb to her clit.

Beckett reached for the hand he had on her stomach and dragged it up to wrap around her breast, her own hand still laying on top of his.

He could feel her walls begin to flutter around his fingers as they continued to plunge in and out of her. Leaning down again, he took his thumb away and reattached his lips to her clit. The suction and rapid flicking of his tongue had her writhing on the bed sheets as he brought her to her climax.

She fell off the cliff as the pleasure coursed through her over and over, running all throughout her body.

"God, Castle," she gasped out.

"I'm flattered, but my first name's Rick," he told her teasingly.

When she came down from her high, she asked, "How many times are you gonna say that? What's that about the 15th time?"

"Maybe I wouldn't have to say it if you'd just stop confusing me with God," he said with a charming grin. "I mean, I know I'm a sex god, but I don't think I'll be replacing my first name with the Man Upstairs." Castle crawled up her body and planted a wet kiss on her lips. She could still taste remnants of herself which turned her on to no end.

"You're a jackass," she told him.

"Hey! I thought you loved my ass," he replied, yelping when she grabbed it and squeezed.

"Oh, I do, Castle. I really, really do. Now, how about you get that fine ass out of those pants."

Not wasting another second, the man did as instructed. Yanking off his shoes and socks, he shed his pants and boxers, leaving the two of them as equally naked as the other.

When he climbed on top of her, she flipped them so that he was now the one lying on his back. Smiling deviously, she straddled his legs and bent her head down near his groin. He was already hard—going down on her was such a turn on for him—so all she had to do was simply wrap her mouth around the head. One hand came up to wrap around the base and slowly pump as her tongue licked the tip.

Castle's eyes rolled to the back of his head as he fought off coming too early and embarrassing himself. He felt like he could explode at minute and the wicked things that his fiancée could do with her mouth were even worse than what he could do with his.

The warm, wet cavern encased him as she took him deeper. _Shit, I won't last if she keeps this up,_ he thought.

"Kate. Kate, stop," he told her. "This'll be over far too quickly if you don't."

Reluctantly, she released him. Positioning herself over his hips, she guided him to her entrance. Without any preamble she swiftly sank onto him, twin groans resonating from both of them.

The detective captured her bottom lip between her teeth and threw her head back as she began to ride him. Her hands came back and rested on his thighs behind her as she leaned back.

This was one of the most exposed positions Castle had ever seen her in. His hands settled on her waist as he helped her move above him. His hips thrust up every time she would thrust down, meeting her with equal force.

Her thighs were straining with the effort it took to keep moving the way she was.

Feeling the need to be closer to her, Castle lifted his upper half off the mattress. One hand came to rest at the small of her back while the other planted itself on the bed behind him, holding him up and adding leverage to drive up into Beckett.

This move brought his face to the junction between her neck and shoulder. His teeth latched on as he bit hard enough to leave a mark. Her moan echoed throughout the room.

The brown-haired woman forewent her current position and instead wrapped her arms around her fiancé's neck, moving faster and faster with each passing minute. Her short breaths and pants were pouring into his ear. She captured his earlobe in her mouth and sucked on lightly.

"Fuck, Kate, I'm not gonna last much longer," he warned her. The flames in his belly were quickly getting fanned higher and higher. He could tell his release was coming very soon.

"Right there with you, babe," she panted. "Just a little more. Please."

He knew what she meant. The hand that was placed on her back snuck around to her front and dropped to where he was rapidly plunging in and out of her. Circling her clit, he felt her walls clench tightly around him. Picking up the pace, his hips slammed up into hers as she shattered.

"Fuck, Castle!" she screamed, her pleasure overtaking her sense of volume control.

Her release had triggered his so he spilled into her, grunting and groaning her name over and over like a mantra. His face was buried in her neck where several strands of her hair were sticking to his sweaty skin. Both of his arms wound tightly around her as he fell back onto the mattress, Beckett coming with him.

Letting him slip out of her, she draped herself over his side, her leg entwining with his, her hand resting over his thumping heart. Her head laid on his shoulder as his arm curled protectively around her.

They were lying in silence for several long minutes. The sound of their harsh breathing gradually calming down was the only noise to be heard. Suddenly, Castle said, "Looks like I wasn't just 'in your veins' tonight, huh?"

Slowly, a smile spread across her face. Her chuckle quickly turned into full laughter as he joined her. Reaching behind her, she clutched a pillow and whacked him with it. "You are such a pervert. I can't believe I'm marrying you."

"Well, I guess I'm just in your veins and you can not get me out."

"Yeah, I guess you are," she said, snuggling closer to him.

"Good. 'Cause I plan on sticking around for a _long_ time."

**A/N: Thank you to those of you who read this. Feel free to review or favorite if it pleases you. Remember, this was only my second time writing smut so go easy on me.**


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